1. Field of the Invention
The present invention relates to a compact one touch pneumatic wrench, and more particularly to a cylinder having an improved air passage to achieve one touch function and a housing mad of engineering plastic material.
2. Description of the Prior Art
The work principle of a pneumatic wrench is that compressed air passes through a speed adjustment mechanism and enters a cylinder for pushing blades to rotate and drive a rotor. A percussion mechanism is to generate alteration impact loading of transient high energy. Due to great twisting movement and better safety, pneumatic wrenches are widely used to assemble productions lines and disassemble nuts.
As shown in FIG. 13, a conventional pneumatic wrench comprises a speed adjustment mechanism and a rotating mechanism which are separated from a cylinder. Compressed air enters the cylinder for pushing blades to rotate and drive a rotor. A percussion mechanism is to generate twisting movement. The speed adjustment mechanism is separated from the cylinder, its outer housing must be made of metallic material, and airtight processing must be done to ensure an airtight passage. This conventional wrench is larger in size and heavy and the cost is high. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to improve the aforesaid problems of the conventional pneumatic wrench.